A court in the US has heard cult leader Keith Raniere considered himself a brilliant self-help guru who was a threat to the government and could control the weather.

Those myths and other oddities about the spiritual leader of the secretive upstate New York organisation called NXIVM were detailed yesterday by a former group official testifying at the 58-year-old’s federal trial.

Filmmaker Mark Vicente also took the chance to describe his despair over learning about allegations that Raniere put his power to a darker use by assembling a harem of sex slaves branded with his initials.

The NXIVM (NEX’-ee-um) defector and former board of directors member took off his glasses and appeared to wipe away tears when a prosecutor asked him to read to himself a copy of the group’s mission statement about Raniere’s prescription for enlightenment.

“It’s a fraud,” he said after he composed himself. “It’s a lie.”

Vicente’s testimony came on the third day of the trial in federal court in Brooklyn, where Raniere has pleaded to sex-trafficking and other charges.

His lawyers have claimed that any sexual contact he had with female followers was consensual.

He wasn’t charged in the case, but Bronfman and TV actress Allison Mack are among five co-defendants of Raniere who have pleaded guilty.

Prosecutors used Vicente to describe how NXIVM members used a “sales pitch” promising Raniere’s new age methods would help them cast off their irrational fears. He said they paid $6,000 (AU$8,500) tuition to take the first of a series of courses that would elevate them to different levels of achievement as long as they also recruited new members - what prosecutors have described as pyramid scheme.

There were various ploys and constant paranoia: Raniere cooked up new curriculums as a way to bolster finances that were kept secret.

Cameras and other technology - portrayed to followers as an internal communications system – were actually used to spy on them, just as Raniere believed the government was spying on him because he knew too much.